The present invention relates to an anti-locking brake system for automotive vehicles of the type including a master cylinder, means for regulating the pressure supplied to the wheel brakes, and an ALC-control device. The control device includes a monitoring device and at least one brake pressure distributing valve comprising a control piston, a valve closing member and a control spring which are disposed in the rear axle brake circuit and which provide pressure decrease only in case of failure of the anti-locking system.
Brake systems of this type are known from German patent document DE-OS No. 37 42 173, wherein the actuation of the valve closing member is effected through a force-applying piston in communication with the valve closing member. One of the force applying faces of the piston is loaded by the master cylinder pressure and the other of the force applying faces is associated with a control chamber in switchable communication with the master cylinder. While that solution provides for a particularly safe brake system optimally using the brake force of the rear wheel brakes, the design of the re-switchable brake force distributing valve requires extensive mechanical efforts and manufacturing costs and comparatively large assembly space requirements.
It is, therefore, an object of the present invention to provide an anti-locking brake system of the type described which is of a simple yet compact design and which is easy to assemble and to adjust.